4th October 2012 - Claims that a rise in allergies is down to a modern preoccupation with cleanliness is a myth, say scientists.
A report from the International Scientific Forum on Home Hygiene challenges the claim that the epidemic rise in allergies is because we live in sterile homes and are too fond of antiseptic wipes and bleach. Instead, the authors say, it is because we are losing touch with mostly harmless microbial 'old friends'.
Furthermore, putting distance between ourselves and these organisms, which can occur in indoor and outdoor environments, may be a factor behind a range of inflammatory diseases such as type 1 diabetes, bowel disease, multiple sclerosis (MS) and some cancers.
Researchers from the London School of Hygiene and Tropical Medicine and University College London say that a leading explanation for the rise in allergies emerged in the late 1980s, putting it down to smaller family sizes, higher standards of cleanliness and presumed less contact with childhood infections. This was interpreted by the media as the idea that our modern society had become 'too clean'.
However, the scientists behind the latest review, which examines 20 years of research, say this notion was always an over simplification but one that has persisted because it is easier to understand than a complicated range of factors.
Presenting the report 'The Hygiene Hypothesis and its implications for home hygiene, lifestyle and public health' at a conference in Liverpool, co-author Dr Rosalind Stanwell-Smith says in a statement that "allergies and chronic inflammatory diseases are serious health issues and it’s time we recognised that simplistically talking about home and personal cleanliness as the cause of the problem is ill-advised, because it’s diverting attention from finding workable solutions and the true, probably much more complex, causes".
She continues: "If worrying about ‘being too clean’ results in people needlessly exposing themselves and their children to pathogens that can make them ill, this would clearly be dangerous."
An urban environment
The authors say that over the last century our society has been transformed from a mainly rural lifestyle to an urban, concrete and plastic world with cleaner water and safer sanitation, bringing with it monumental changes to diet and our home and working environments.
Dr Stanwell Smith argues that "since the 1800s, when allergies began to be more noticed, the mix of microbes we’ve lived with, and eaten, drunk and breathed in has been steadily changing". She continues: "Some of this has come through measures to combat infectious diseases that used to take such a heavy toll in those days - in London, one in three deaths was a child under five. These changes include clean drinking water, safe food, sanitation and sewers, and maybe overuse of antibiotics.
"Whilst vital for protecting us from infectious diseases, these will also have inadvertently altered exposure to the ‘microbial friends’ which inhabit the same environments."
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